Explore and develop the use of continuous wave carbon dioxide lasers to help prevent tooth decay. The potential usefulness of lasers to prevent decay-like lesions in-vitro has been reported. Animal and clinical trials need to be conducted, but first the biological safety parameters need to be established. Carbon dioxide lasers appear to be best suited for use with enamel and preventative dentistry. We propose to establish for the continuous wave carbon dioxide laser the power density threshold limits (joules/cm2) at which point damage or potential damage begins to occur to dental pulp and enamel as a result of the laser. These will be established through pulp histology studies, pulp temperature studies and S.E.M. enamel studies using dogs' teeth in-vivo, extracted human teeth, standard histology and S.E.M. techniques. The laser power will be increased by controlled increments until thresholds are reached and safety ranges established. The correlation of results from these four studies will allow us to proceed with animal and clinical decay prevention studies within the defined limits of safety to avoid damage to the pulp and/or enamel.